The present invention can relate to an illuminating apparatus and to a projector.
There have been demands for high luminance projectors, and in response to such demands, projectors having two light source devices (so called a ‘two-lamp type projector’) have been proposed. FIG. 10 is a schematic diagram of a related art two-lamp type projector 900.
As shown in FIG. 10, the related art two-lamp type projector 900 is equipped with a two-lamp type illuminating apparatus 900 that emits approximately parallel light to an illumination target area side, a liquid crystal device 970 that modulates illuminating light flux from the illuminating apparatus 902 in response to image information, and a projection optical system 980 that projects the modulated light by the liquid crystal device 970. The illuminating apparatus 902 is equipped with two light source devices 910a and 910b, a triangular prism 903 that synthesizes light components emitted from the two light source devices 910a and 910b, a collimating lens that approximately collimates the synthesized light by the triangular prism 903, a first lens array 920 having a plurality of first small lenses that divide the light from the collimating lens 918 into a plurality of partial light flux, a second lens array 930 having a plurality of second small lenses corresponding to the first small lenses, a polarization optical system 940 that aligns incident light into one type of linear polarized light to emit, and a superposing lens 950 that superposes each of the partial light flux from the polarization optical system 940 onto the illumination target area (for example, please refer to JP-A-2002-72083).
According to the two-lamp type projector 900 of the related art as described above, since the illuminating apparatus 902 with two light source devices 910a and 910b is used as an illuminating apparatus, projectors with higher brightness could be obtained compared with the projectors according to the related art
However, in the above-mentioned two-lamp type projector 900 according to the related art has problems in that, if light emission of the light emitting tube in either one of the two light source devices 910a and 910b is weakened or stopped, distribution of in-plane light intensity on the illumination target area becomes non-uniform, and therefore the quality of a projected image is degraded. These problems are not limited to the two-lamp type projectors, and are also caused in projectors having three or more light source devices.